Thessalonika (Thessaloniki) was more important towards the later stages of the Roman Empire, when it was a center for business and trade.

Situated on the Thermaic Gulf of the Aegean Sea and being on on the trade route that connected Constantinople with Dyrrhachium which connected Europe to Asia,Thessalonika became a capital for one of the four Roman districts of Macedonia, and was the site of a major harbour.

The Roman Forum in Thessaloniki
image: Wikimedia